radeonsi: document a CP DMA bug that doesn't need a workaround yet
radeonsi: document a CP DMA bug that doesn't need a workaround yet

This one is easy to miss, because it's not documented in any internal doc.

Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler